feat(desktop): embed BoosAPI Desktop client as a subproject

Vendor the rebranded BoosAPI Desktop client (Tauri + Vue) into metapi as
a monorepo subdirectory under desktop/. Source only — node_modules,
dist, Cargo target and the upstream .git history are excluded.

desktop/ keeps its own independent Cargo workspace (desktop/src-tauri
with crates/*); it is not part of the backend boosapi crate, so a
`cargo check` at the metapi root still compiles only the backend. Build
the desktop app from desktop/src-tauri per desktop/README.md.

Note: app icons are still placeholder assets pending the final BoosAPI
logo. The updater signing keys live outside the repo and are not
included.

desktop/src-tauri/crates/open-agent-sdk/tests/costtracker_test.rs

@@ -0,0 +1,195 @@
+use open_agent_sdk::costtracker::CostTracker;
+use open_agent_sdk::types::Usage;
+
+#[tokio::test]
+async fn test_cost_tracker_new() {
+    let tracker = CostTracker::new();
+    assert_eq!(tracker.total_cost().await, 0.0);
+    assert_eq!(tracker.total_tokens().await, 0);
+}
+
+#[tokio::test]
+async fn test_cost_tracker_add_usage() {
+    let tracker = CostTracker::new();
+
+    let usage = Usage {
+        input_tokens: 1000,
+        output_tokens: 500,
+        cache_creation_input_tokens: 0,
+        cache_read_input_tokens: 0,
+    };
+
+    tracker.add_usage("claude-sonnet-4-6-20250514", &usage).await;
+
+    assert_eq!(tracker.total_tokens().await, 1500);
+    assert!(tracker.total_cost().await > 0.0);
+}
+
+#[tokio::test]
+async fn test_cost_tracker_multiple_models() {
+    let tracker = CostTracker::new();
+
+    tracker
+        .add_usage(
+            "claude-sonnet-4-6-20250514",
+            &Usage {
+                input_tokens: 1000,
+                output_tokens: 500,
+                ..Default::default()
+            },
+        )
+        .await;
+
+    tracker
+        .add_usage(
+            "claude-opus-4-6-20250514",
+            &Usage {
+                input_tokens: 500,
+                output_tokens: 200,
+                ..Default::default()
+            },
+        )
+        .await;
+
+    assert_eq!(tracker.total_tokens().await, 2200);
+
+    let sonnet_usage = tracker
+        .get_model_usage("claude-sonnet-4-6-20250514")
+        .await;
+    assert!(sonnet_usage.is_some());
+    assert_eq!(sonnet_usage.unwrap().input_tokens, 1000);
+
+    let opus_usage = tracker
+        .get_model_usage("claude-opus-4-6-20250514")
+        .await;
+    assert!(opus_usage.is_some());
+    assert_eq!(opus_usage.unwrap().input_tokens, 500);
+}
+
+#[tokio::test]
+async fn test_cost_tracker_accumulates() {
+    let tracker = CostTracker::new();
+
+    let usage = Usage {
+        input_tokens: 1000,
+        output_tokens: 500,
+        ..Default::default()
+    };
+
+    tracker.add_usage("claude-sonnet-4-6-20250514", &usage).await;
+    tracker.add_usage("claude-sonnet-4-6-20250514", &usage).await;
+
+    assert_eq!(tracker.total_tokens().await, 3000);
+
+    let model_usage = tracker
+        .get_model_usage("claude-sonnet-4-6-20250514")
+        .await
+        .unwrap();
+    assert_eq!(model_usage.input_tokens, 2000);
+    assert_eq!(model_usage.output_tokens, 1000);
+}
+
+#[tokio::test]
+async fn test_cost_tracker_durations() {
+    let tracker = CostTracker::new();
+
+    tracker.add_api_duration(100).await;
+    tracker.add_api_duration(200).await;
+    tracker.add_tool_duration(50).await;
+
+    let summary = tracker.summary().await;
+    assert_eq!(summary.api_duration_ms, 300);
+    assert_eq!(summary.tool_duration_ms, 50);
+}
+
+#[tokio::test]
+async fn test_cost_tracker_code_changes() {
+    let tracker = CostTracker::new();
+
+    tracker.add_code_changes(10, 5).await;
+    tracker.add_code_changes(20, 3).await;
+
+    let summary = tracker.summary().await;
+    assert_eq!(summary.lines_added, 30);
+    assert_eq!(summary.lines_removed, 8);
+}
+
+#[tokio::test]
+async fn test_cost_tracker_web_searches() {
+    let tracker = CostTracker::new();
+
+    tracker.add_web_search().await;
+    tracker.add_web_search().await;
+
+    let summary = tracker.summary().await;
+    assert_eq!(summary.web_searches, 2);
+}
+
+#[tokio::test]
+async fn test_cost_calculation_sonnet() {
+    let tracker = CostTracker::new();
+
+    // 1M input + 1M output for sonnet = $3 + $15 = $18
+    tracker
+        .add_usage(
+            "claude-sonnet-4-6-20250514",
+            &Usage {
+                input_tokens: 1_000_000,
+                output_tokens: 1_000_000,
+                ..Default::default()
+            },
+        )
+        .await;
+
+    let cost = tracker.total_cost().await;
+    assert!((cost - 18.0).abs() < 0.01);
+}
+
+#[tokio::test]
+async fn test_cost_calculation_opus() {
+    let tracker = CostTracker::new();
+
+    // 1M input + 1M output for opus = $15 + $75 = $90
+    tracker
+        .add_usage(
+            "claude-opus-4-6-20250514",
+            &Usage {
+                input_tokens: 1_000_000,
+                output_tokens: 1_000_000,
+                ..Default::default()
+            },
+        )
+        .await;
+
+    let cost = tracker.total_cost().await;
+    assert!((cost - 90.0).abs() < 0.01);
+}
+
+#[tokio::test]
+async fn test_get_all_usage() {
+    let tracker = CostTracker::new();
+
+    tracker
+        .add_usage(
+            "model-a",
+            &Usage {
+                input_tokens: 100,
+                ..Default::default()
+            },
+        )
+        .await;
+    tracker
+        .add_usage(
+            "model-b",
+            &Usage {
+                input_tokens: 200,
+                ..Default::default()
+            },
+        )
+        .await;
+
+    let all = tracker.get_all_usage().await;
+    assert_eq!(all.len(), 2);
+    assert!(all.contains_key("model-a"));
+    assert!(all.contains_key("model-b"));
+}